It’s a classic, though not a radio hit. From Prine to Carly Simon to Bonnie Raitt to someone on Lower Broadway later today, people have been singing it for 40 years now.

He wrote it when he was in his 20s, far too young to be writing wise songs about aging and desperation. He wrote it while picturing a woman standing over dirty dishes, hoping for miraculous escape while attending to unrelenting mundanity.

I’m a Prine fan. I knew all that stuff I just wrote long before I just wrote it.

What I didn’t know until visiting a new Country Music Hall of Fame and Museum exhibit, called “It Took Me Years to Get These Souvenirs,” was that he wrote it in red ink. I always thought red ink was for correction, not creation. From now on, I shall write only in red ink.

There it is, in the museum’s second-floor gallery: red ink that begins with a line Prine still sings convincingly, “I am an old woman, named after my mother.” Then he wrote, “My old man is another kid that’s grown old.” But Prine crossed over red ink with black, and in the left margin of the notebook page he wrote the word “child.”

Not “kid that’s grown old.”

“Child that’s grown old.”

Means the same thing. But it’s different.

Songs recorded by many

Prine’s manuscripts at the exhibit are filled with subtle changes that elevated great songs into the realm of brilliance.

In “Jesus, the Missing Years” — a song that drew an angry letter from a fan charging sacrilege, a letter that is exhibited at the museum — Prine changed “Once, he even opened up for old George Jones” to “Once, he even opened up a three-way package for old George Jones.”

George Jones should’ve recorded some John Prine songs. Some country stars have.

Don Williams had a No. 1 hit with “Love Is on a Roll,” and George Strait had another one with “I Just Want to Dance With You,” which won Prine the most unusual trophy of his well-trophied career, a “Golden Pick” award from “Country Weekly” for “best line-dance song.” (That one’s on display, too.)

Singer John Prine pose with old Big Boy statues for his song called "There's a Smile on Every Face out there." (Ricky Rogers / The Tennessean) 1/14/1985

But for the most part, Prine has existed outside of the country mainstream. Why, then, a Country Music Hall of Fame and Museum exhibit?

“It’s very important to keep the story of this music in balance,” said exhibit curator Mick Buck. “It’s not just about what was on the charts. Mr. Prine is widely accepted as one of the greatest, most influential songwriters of his generation, not only in country but in rock and other genres. When he was first writing songs, his biggest influences were Hank Williams, Roger Miller and Bob Dylan. So, even though he’s never been marketed as a country artist, he’s a vital link in the bigger story of country music.”

Tracing a journey

The new exhibit, which will be up for the next six months, focuses on the pivot points in the journey of Prine, who announced this week that he will undergo surgery next month for lung cancer.

The display case holds his first guitar, a Kentucky blue, 1960 Silvertone of the sort that could be purchased a half-century ago in the Montgomery Ward catalog.

It also features posters and photos of Prine with Kris Kristofferson and Steve Goodman. In 1971, Goodman (who wrote the country-folk standard “City of New Orleans”) was opening a series of shows for the already-established Kristofferson, and Kristofferson kept paying him compliments. Goodman said something along the lines of “If you like my stuff, you should hear my friend John.” And Goodman dragged Kristofferson to hear Prine at a Chicago club.

They pulled the chairs from the late-night tables, Prine unpacked his guitar and played some songs, and the result was that Kristofferson was soon lobbying Atlantic Records (successfully) to give Prine a record deal.

It was an act of kindness from Goodman that kicked off a remarkable career and gave you and me a whole lot of John Prine songs to enjoy.

Other pivot points were Prine’s eponymous 1971 debut album, which brought him to popular attention, and his 1991 “The Missing Years.” That album, released on his and old friend Al Bunetta’s label, Oh Boy Records, redirected critics and fans to the pleasures found within Prine’s songs, which Chicago Tribune writer Lynn Van Matre described as “Goofily surreal and straightforwardly sentimental by turns.”

The Grammy Prine won for “The Missing Years” is on display at the museum, plus one he won in 2006 for “Fair & Square.”

Also on display is a summation from Bob Dylan, one of Prine’s primary inspirations. “Prine’s stuff is pure Praustian existentialism,” Dylan said. “Midwestern mind trips to the nth degree, and he writes beautiful songs.”

He does.

He writes them.

And then he rewrites them.

A kid becomes a child, and then the whole thing hits home.

If You Go

What: “John Prine: It Took Me Years to Get These Souvenirs” exhibit

When: Through May

Where: Country Music Hall of Fame and Museum, 222 Fifth Ave. S.

Admission: Included in museum admission, $22 for adults, $14 for kids ages 6-17, free for ages 5 and younger.